Method and system for controlling the height of an agricultural implement relative to the ground

Abstract

In one aspect, a method is disclosed for automatically controlling a height of an implement of an agricultural work vehicle relative to a ground surface. The method may include monitoring the height of the implement and a vehicle speed; determining an implement height error by comparing the height of the implement with a predetermined target height; and calculating a sensitivity factor based on a sensitivity setting. When the monitored vehicle speed is greater than a predetermined speed threshold, the sensitivity factor may equal a first constant sensitivity value that is proportional to the sensitivity setting. The method may include reducing the sensitivity factor to less than the first constant sensitivity value when the monitored vehicle speed becomes less than the predetermined speed threshold and adjusting the height of the implement relative to the ground surface based on the implement height error and the sensitivity factor.

1 - 20 . (canceled) 
     
     
         21 . A method for automatically controlling a height of an implement of an agricultural work vehicle relative to a ground surface, the method comprising:
 monitoring, with one or more computing devices, each of the height of the implement relative to the ground surface and a vehicle speed of the agricultural work vehicle relative to the ground surface;   determining, with the one or more computing devices, an implement height error by comparing the height of the implement with a predetermined target height;   calculating, with the one or more computing devices, a sensitivity factor according to a predetermined relationship that specifies values for the sensitivity factor as function of the monitored vehicle speed, the values for the sensitivity factor differing at least in part depending on whether the monitored vehicle speed exceeds or falls below a predetermined speed threshold; and   adjusting, with the one or more computing devices, the height of the implement relative to the ground surface based on the implement height error and the sensitivity factor;   wherein:   for vehicle speeds that exceed the predetermined speed threshold, the predetermined relationship specifies that the sensitivity factor is equal a constant sensitivity value; and   for vehicle speeds that fall below the predetermined speed threshold, the predetermined relationship specifies that the sensitivity factor is less than the constant sensitivity value and varies with changes in the monitored vehicle speed.   
     
     
         22 . The method of  claim 21 , wherein the predetermined function specifies that the sensitive factor varies linearly with changes in the monitored vehicle speed for vehicle speeds that fall below the predetermined speed threshold. 
     
     
         23 . The method of  claim 21 , wherein the predetermined function specifies that the sensitive factor varies non-linearly with changes in the monitored vehicle speed for vehicle speeds that fall below the predetermined speed threshold. 
     
     
         24 . The method of  claim 21 , wherein the predetermined relationship comprises a discontinuous function having a first discontinuity at the predetermined speed threshold. 
     
     
         25 . The method of  claim 24 , wherein the discontinuous function includes one or more additional discontinuities at one or more respective vehicle speeds below the predetermined speed threshold such that the sensitivity factor varies in a stepwise manner with changes in the monitored vehicle speed at vehicle speeds that fall below the predetermined speed threshold. 
     
     
         26 . The method of  claim 21 , wherein sensitivity factor varies in a stepwise manner with changes in the monitored vehicle speed at vehicle speeds that fall below the predetermined speed threshold. 
     
     
         27 . The method of  claim 21 , further comprising:
 computing a proportional signal based on a product of a proportional signal gain and the implement height error, the proportional signal gain being based on the sensitivity factor;   wherein adjusting the height of the implement relative to the ground surface comprises adjusting the height of the implement based on the proportional signal   
     
     
         28 . The method of  claim 21 , further comprising:
 computing an integral signal based on an integral of the implement height error with respect to time; and   modifying the integral signals based on the sensitivity factor;   wherein adjusting the height of the implement comprises adjusting the height of the implement further based on the modified integral signal.   
     
     
         29 . The method of  claim 21 , wherein the sensitivity factor is based at least in part on a sensitivity setting selected by an operator of the agricultural work vehicle, the sensitivity setting being associated with a vehicle speed setting that is suitable for performing an agricultural operation with the implement with respect to the ground surface. 
     
     
         30 . The method of  claim 21 , wherein adjusting the height of the implement includes controlling a valve that is fluidly coupled with an actuator configured to raise and lower the implement. 
     
     
         31 . A height control system for an implement of an agricultural work vehicle, the control system comprising:
 an implement connected with the agricultural work vehicle;   an implement height sensor configured to detect a height of the implement relative to a ground surface;   a controller communicatively coupled to the implement height sensor, the controller including a processor and associated memory, the memory storing instructions that, when executed by the processor, configure the implement controller to:
 monitor each of the height of the implement relative to the ground surface and a vehicle speed of the agricultural work vehicle relative to the ground surface; 
 determine an implement height error by comparing the height of the implement with a predetermined target height; 
 calculate a sensitivity factor according to a predetermined relationship that specifies values for the sensitivity factor as function of the monitored vehicle speed, the values for the sensitivity factor differing at least in part depending on whether the monitored vehicle speed exceeds or falls below a predetermined speed threshold; and 
 adjust the height of the implement relative to the ground surface based on the implement height error and the sensitivity factor; 
   wherein:   for vehicle speeds that exceed the predetermined speed threshold, the predetermined relationship specifies that the sensitivity factor is equal a constant sensitivity value; and   for vehicle speeds that fall below the predetermined speed threshold, the predetermined relationship specifies that the sensitivity factor is less than the constant sensitivity value and varies with changes in the monitored vehicle speed.   
     
     
         32 . The height control system of  claim 31 , wherein the predetermined function specifies that the sensitive factor varies linearly with changes in the monitored vehicle speed for vehicle speeds that fall below the predetermined speed threshold. 
     
     
         33 . The height control system of  claim 31 , wherein the predetermined function specifies that the sensitive factor varies non-linearly with changes in the monitored vehicle speed for vehicle speeds that fall below the predetermined speed threshold. 
     
     
         34 . The height control system of  claim 31 , wherein the predetermined relationship comprises a discontinuous function having a first discontinuity at the predetermined speed threshold. 
     
     
         35 . The height control system of  claim 34 , wherein the discontinuous function includes one or more additional discontinuities at one or more respective vehicle speeds below the predetermined speed threshold such that the sensitivity factor varies in a stepwise manner with changes in the monitored vehicle speed at vehicle speeds that fall below the predetermined speed threshold. 
     
     
         36 . The height control system of  claim 31 , wherein sensitivity factor varies in a stepwise manner with changes in the monitored vehicle speed at vehicle speeds that fall below the predetermined speed threshold. 
     
     
         37 . The height control system of  claim 31 , wherein the controller is further configured to compute a proportional signal based on a product of a proportional signal gain and the implement height error, the proportional signal gain being based on the sensitivity factor, and wherein the controller is further configured to adjust the height of the implement based on the proportional signal. 
     
     
         38 . The height control system of  claim 31 , wherein the controller is further configured to compute an integral signal based on an integral of the implement height error with respect to time and modify the integral signal based on the sensitivity factor, wherein the controller is configured to adjust the height of the implement based on the integral signal. 
     
     
         39 . The height control system of  claim 31 , wherein the sensitivity factor is based at least in part on a sensitivity setting selected by an operator of the agricultural work vehicle, the sensitivity setting being associated with a vehicle speed setting that is suitable for performing an agricultural operation with the implement with respect to the ground surface. 
     
     
         40 . The height control system of  claim 31 , further comprising an actuator configured to raise and lower the implement relative to the ground surface and a control valve fluidly coupled with the actuator, and wherein the controller is configured to control the flow of a fluid to the actuator using the control valve to adjust the height of the implement relative to the ground surface.